[Heathkit] HW101-Trouble Shooting Techniques

[Pastor-kc1di]

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-------Original Message-------=0D
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From: Ben McKinney=0D
Date: Tuesday, January 07, 2003 9:49:02 AM=0D
To: heathkit@mailman.qth.net=0D
Subject: [Heathkit] HW101-Trouble Shooting Techniques=0D
 =0D
Gang:=0D
I am in the process of bringing an old HW-101 back to life and need some =
of
your assistance and guidance.=0D
The issue is associated with the receiver portion of the radio (have not
begun the attack on the transmitter chain yet, ...coming).=0D
I got the receiver up and running and honestly the darn thing sounds
excellent, good sensitivity, good S meter / AVC action, stable, etc. I ha=
ve
gone thru and replaced all of the electrolytic caps. Have rebuilt the 23A
power supply top to bottom Caps/ diodes, grounding, etc.=0D
Here is where I need some help. The crazy thing has a intermittant "crack=
le
/ frying" sound that comes and goes. It is temperature related. Over an h=
our
it becomes very imtermittant. I am assuming a Cap / connection somewhere.
When the crackle is in, turning the Audio Gain down and or RF Gain down
doesn't kill it. I have tried the "freeze" sprays on boards / components =
and
no real luck. Here is the question...What search techniques could I try t=
o
narrow it to a particular area of the circuit?? I do have an O-scope. Any
other search and destroy ideas would also be appreciated.=0D
In advance thanks for any help!...=0D
73 Ben=0D
K5HQV=0D
=0D
Hi Ben,=0D
=0D
First thing I would do is a very carful visual inspection of the areas=20
close to the tube socket.. Many 101's develop cold soldier joint because =
of
the heating and cool of the tube sockets.  Also I had one that would have
intermitent audio and that was due to poor circut board grounding.  make
sure all screws are tight and there is no corrosion around them.=0D
=0D
hope this is of help.=0D
73 Dave KC1DI=0D
=0D
=2E

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